Contributions
Abstract: PB2499
Type: Publication Only
Background
The hemoglobinopathies (HGP) are a group of hereditary disorders in which there is abnormal production or abnormal structure of the hemoglobin (Hb) molecule. These are the most frequent group of genetic disorders worldwide. They are broadly categorized into two major groups: thalassemias and structural variants of hemoglobin. HGP have become much more common recently in northern and central Europe, including Portugal, due to immigration.
Aims
The aim of this study was to analyze the incidence of HGP in all samples screened for HGP in a central hospital during the last 10 years.
Methods
Retrospective study performed in a central and university hospital of Porto, Portugal. A total of 4131 samples of 3886 patients, studied from January 2007 to December 2016, were included. These samples were collected in EDTA-K3 tubes and were analyzed in an automatic hematological counter to obtain red blood cell count with erythrocyte indices. The next step of diagnosis workout consisted on Hb tests: high performance liquid chromatography, electrophoresis and, sometimes solubility test. When detected abnormal structural Hb, samples were tested by molecular biology to identify the Hb variant.
Results
From all the patients studied (n=3886), 19.8% (n=771) had Hb genetic disorders and were subdivided into two main groups: β-thalassemia syndromes (71.5%; n=551) and structural Hb variants (28.5%; n=220). The most frequent HGP were β-thalassemia (n=550 β-thalassemia minor and n=1 β-thalassemia major) and Hb AS (14.5%; n=112), followed by Hb Lepore (5.1%; n=39), Hb SS (2.9%; n=22), Hb AD (2.2%; n=17) and Hb AC (1.0%; n=8). Other rare Hb variants detected were: Hb AE (0.5%; n=4), Hb Indianopolis (0.5%; n=4), Hb Koln (0.4%; n=3), Hb SC (0.4%; n=3), ∆-chain variant Hb A2 (0.3%; n=2), Hb Himeji (0.1%; n=1), Hb Setif (0.1%; n=1), Hb Strasbourg (0.1%; n=1) and Hb Porto Alegre (0.1%; n=1). Concomitant β-thalassemia and Hb AS was also present in two of our patients (0.3%; n=2).
Conclusion
Our data are concordant with previous epidemiological studies. It is noteworthy that our sampling included HGP screening samples and not the whole population and therefore we found higher levels of genetic Hb disorders. The α-thalassemia syndromes were not detected by our methods, as characterization of these diseases requires DNA-based α-globin gene testing. For this reason, some of the samples studied for HGP screening may have gone undetected. HGP are a public health issue and therefore early detection and characterization of the HGP is crucial so that appropriate counselling and treatment can be provided to couples through prenatal screening and families who may be at risk of having HGP. The reinforcement of these measures can lead to the reduction of incidence and morbidity associated with these disorders.
Session topic: 28. Thalassemias
Keyword(s): Hemoglobin variants, Hemoglobinopathy, Thalassemia
Abstract: PB2499
Type: Publication Only
Background
The hemoglobinopathies (HGP) are a group of hereditary disorders in which there is abnormal production or abnormal structure of the hemoglobin (Hb) molecule. These are the most frequent group of genetic disorders worldwide. They are broadly categorized into two major groups: thalassemias and structural variants of hemoglobin. HGP have become much more common recently in northern and central Europe, including Portugal, due to immigration.
Aims
The aim of this study was to analyze the incidence of HGP in all samples screened for HGP in a central hospital during the last 10 years.
Methods
Retrospective study performed in a central and university hospital of Porto, Portugal. A total of 4131 samples of 3886 patients, studied from January 2007 to December 2016, were included. These samples were collected in EDTA-K3 tubes and were analyzed in an automatic hematological counter to obtain red blood cell count with erythrocyte indices. The next step of diagnosis workout consisted on Hb tests: high performance liquid chromatography, electrophoresis and, sometimes solubility test. When detected abnormal structural Hb, samples were tested by molecular biology to identify the Hb variant.
Results
From all the patients studied (n=3886), 19.8% (n=771) had Hb genetic disorders and were subdivided into two main groups: β-thalassemia syndromes (71.5%; n=551) and structural Hb variants (28.5%; n=220). The most frequent HGP were β-thalassemia (n=550 β-thalassemia minor and n=1 β-thalassemia major) and Hb AS (14.5%; n=112), followed by Hb Lepore (5.1%; n=39), Hb SS (2.9%; n=22), Hb AD (2.2%; n=17) and Hb AC (1.0%; n=8). Other rare Hb variants detected were: Hb AE (0.5%; n=4), Hb Indianopolis (0.5%; n=4), Hb Koln (0.4%; n=3), Hb SC (0.4%; n=3), ∆-chain variant Hb A2 (0.3%; n=2), Hb Himeji (0.1%; n=1), Hb Setif (0.1%; n=1), Hb Strasbourg (0.1%; n=1) and Hb Porto Alegre (0.1%; n=1). Concomitant β-thalassemia and Hb AS was also present in two of our patients (0.3%; n=2).
Conclusion
Our data are concordant with previous epidemiological studies. It is noteworthy that our sampling included HGP screening samples and not the whole population and therefore we found higher levels of genetic Hb disorders. The α-thalassemia syndromes were not detected by our methods, as characterization of these diseases requires DNA-based α-globin gene testing. For this reason, some of the samples studied for HGP screening may have gone undetected. HGP are a public health issue and therefore early detection and characterization of the HGP is crucial so that appropriate counselling and treatment can be provided to couples through prenatal screening and families who may be at risk of having HGP. The reinforcement of these measures can lead to the reduction of incidence and morbidity associated with these disorders.
Session topic: 28. Thalassemias
Keyword(s): Hemoglobin variants, Hemoglobinopathy, Thalassemia